Decades of breast cancer screening research demonstrating a 20-30% reduction in breast cancer mortality, has led to one of the most successful public health efforts in the U.S. with over 33 million women a year in this country undergo screening mammography. In spite of the tremendous research and health care delivery efforts that have gone into breast cancer screening, optimization remains hampered by the key issues including: a) continued excess mortality and advanced stage of breast cancer; b) demonstrated harms associated with breast cancer screening; c) ambiguity over specific guidelines; d) emergence of new technologies. These issues have been, and continue to be addressed through randomized controlled trials (RCTs) and observational studies of individuals. However, breast cancer screening occurs within complex systems of health care delivery, encompassing individuals, providers, facilities, organizations, and communities. The goal of screening 'the right women with the right test at the right time' is likely to only be achieved by studying breast cancer screening processes within a framework that encompasses individual, provider, and practice-level factors. A shortcoming of prior work has been a relative lack of examining system factors that determine processes of care and ultimately screening outcomes. Recent health care reform initiatives emphasize preventive care, a medical home model, accountability, and use of information systems all of which operate at a systems-level. After at least two decades of breast cancer screening research, a shift to examining the screening process as it plays out within systems is necessary to further improve the effectiveness of screening, and to optimize it for individual women and for populations. This project will provide a systems approach to the entire screening process and will integrate health information technology (IT) into improvement strategies to advance quality, and ultimately women's outcomes. Our main objective is to improve breast cancer screening systems through measurement and feedback through the following specific aims: (1) use a microsystems approach, map the entire breast screening process within heterogeneous health care delivery systems, develop generalizable metrics of process indicators for providers and practices, and assess process change in a health information technology environment; (2) characterize process and screening outcomes in relation to woman-, provider-, and practice-level correlates; and (3) develop and implement a provider and practice-level dashboard tool to measure and report metrics for breast cancer screening processes. This research will provide critical evidence of how breast cancer screening systems work overall, which system factors are salient, and for which subgroups of women, and will begin to contribute tools for improving delivery processes in order to achieve the greatest benefit with the least harm for women individually and from a population level.